Organic light-emitting device

ABSTRACT

An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; m emission units stacked between the first electrode and the second electrode, each emission unit including at least one emission layer; and m−1 charge generating layers respectively located between two adjacent emission units among them emission units, each of the charge generating layers including one n-type charge generating region and one p-type charge generating region, wherein m is an integer of 2 or more, and at least one of the m−1 p-type charge generating regions includes a phosphate-containing compound.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0034046, filed on Mar. 19, 2020, in the Korean Intellectual Property Office, the entire content of which is hereby incorporated by reference.

BACKGROUND 1. Field

One or more embodiments of the present disclosure relate to an organic light-emitting device.

2. Description of Related Art

Organic light-emitting devices are self-emission devices that produce full-color images, and also have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of luminance, driving voltage, and response speed.

Such an organic light-emitting device may include a first electrode located on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode, which are sequentially arranged on the first electrode.

Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transit (e.g., transition or relax) from an excited state to a ground state, thereby generating light.

SUMMARY

Provided is an organic light-emitting device having low driving voltage, high efficiency, and long lifespan.

Additional aspects of embodiments will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

According to an aspect of an embodiment, provided is an organic light-emitting device including:

a first electrode,

a second electrode facing the first electrode,

m emission units stacked between the first electrode and the second electrode, each emission unit including at least one emission layer, and

m−1 charge generating layers respectively located between two adjacent emission units among them emission units, each of the charge generating layers including one n-type charge generating region and one p-type charge generating region,

wherein m is an integer of 2 or more, and

at least one of the m−1 p-type charge generating regions includes a phosphate-containing compound.

According to another aspect of an embodiment, provided is an organic light-emitting device including:

a first electrode,

a second electrode facing the first electrode,

m emission units stacked between the first electrode and the second electrode, each emission unit including at least one emission layer, and

m−1 charge generating layers respectively located between two adjacent emission units among the m emission units, each of the charge generating layers including one n-type charge generating region and one p-type charge generating region,

wherein m is an integer of 2 or more,

at least one of the m emission units further includes a hole transport region between the first electrode and the emission layer, and

at least one selected from the p-type charge generating region and the hole transport region includes a phosphate-containing compound.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIGS. 1 to 4 are each a schematic cross-sectional view of an organic light-emitting device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in more detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of embodiments of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Throughout the disclosure, the expression “at least one of a, b or c” indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

According to an aspect of an embodiment, provided is an organic light-emitting device including:

a first electrode;

a second electrode facing the first electrode;

m emission units stacked between the first electrode and the second electrode and including at least one emission layer; and

m−1 charge generating layers located between two adjacent emission units among them emission units, each of the charge generating layers including one n-type charge generating region and one p-type charge generating region,

wherein m may be an integer of 2 or more, and

at least one of the m−1 p-type charge generating regions may include a phosphate-containing compound.

The emission units are not particularly limited as long as they are units capable of emitting light. For example, one emission unit may include at least one emission layer. As necessary or desired, the emission unit may further include an organic layer, in addition to the emission layer.

As used herein, the variable m indicates the number of the emission units may be selected as necessary or desired, and the upper limit of the number is not particularly limited. For example, the organic light-emitting device may include two, three, four, or five emission units.

With respect to the organic light-emitting device according to an embodiment, m may be 2 or 3, but embodiments of the present disclosure are not limited thereto.

In one embodiment, a maximum emission wavelength of light emitted from at least one emission unit among the m emission units may be different from a maximum emission wavelength of light emitted from at least one emission unit among other emission units. For example, in an organic light-emitting device in which a first emission unit and a second emission unit are stacked, a maximum emission wavelength of light emitted from the first emission unit may be different from a maximum emission wavelength of light emitted from the second emission unit. In some embodiments, emission layers in the first emission unit and the second emission unit may each independently have i) a single-layered structure including (or consisting of) a single layer consisting of a single material, ii) a single-layered structure including (or consisting of) a single layer consisting of a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including (or consisting of) a plurality of different materials. Accordingly, light emitted from the first emission unit or the second emission unit may be single-color light or mixed-color light. In one or more embodiments, in an organic light-emitting device in which a first emission unit, a second emission unit, and a third emission unit are stacked, a maximum emission wavelength of light emitted from the first emission unit may be identical to a maximum emission wavelength of light emitted from the second emission unit, but may be different from a maximum emission wavelength of light emitted from the third emission unit. In one or more embodiments, a maximum emission wavelength of light emitted from the first emission unit, a maximum emission wavelength of light emitted from the second emission unit, and a maximum emission wavelength of light emitted from the third emission unit may be different from each other.

The organic light-emitting device according to an embodiment may include a charge generating layer between two adjacent emission units among the m emission units, wherein the expression “adjacent” means an arrangement relationship of the closest layers among the layers referred to as adjacent. For example, the expression “two adjacent emission units” indicates two emission units that are most closely located among a plurality of emission units. The expression “adjacent” may indicate an arrangement where two layers are physically in contact with each other or an arrangement where another layer that is not described may be located between two layers. For example, an emission unit adjacent to a second electrode indicates an emission unit that is located most closely to the second electrode among a plurality of emission units. In addition, the second electrode and the emission unit may be physically in contact with each other, but other layers that are not described may be located between the second electrode and the emission unit. For example, an electron transport layer may be located between the second electrode and the emission unit.

A charge generating layer is located between two adjacent emission units. One emission unit among the two adjacent emission units and the charge generating layer may be physically in contact with each other, and another layer that is not described may be located between the one emission unit and the charge generating layer. For example, an electron transport layer may be located between an emission unit that is adjacent to a first electrode among the two adjacent emission units and the charge generating layer. As another example, a hole transport layer may be located between an emission unit that is adjacent to a second electrode among the two adjacent emission units and the charge generating layer.

The charge generating layer is a layer that acts as a cathode for injecting electrodes with respect to one emission unit among two adjacent emission units by generating charges or separating charges into holes and electrons and acts as an anode for injecting holes with respect to the other emission unit, which is not directly coupled to an electrode and separates emission units that are adjacent to each other. An organic light-emitting device including m emission units includes m−1 charge generating layers. Because m−1 charge generating layers each include one n-type charge generating region and one p-type charge generating region, an organic light-emitting device including m−1 charge generating layers includes m−1 n-type charge generating regions and m−1 p-type charge generating regions.

For example, the n-type charge generating region may be located between the first electrode and the p-type charge generating region.

FIG. 1 is a schematic cross-sectional view of an organic light-emitting device 10 according to an embodiment. In the organic light-emitting device 10 according to an embodiment, m is 2. For example, in some embodiments, the organic light-emitting device 10 includes two emission units that are a first emission unit 151 and a second emission unit 152.

The organic light-emitting device 10 may include a first electrode 110, a second electrode 190 facing the first electrode 110, a first emission unit 151 between the first electrode 110 and the second electrode 190, a second emission unit 152 between the first emission unit 151 and the second electrode 190, and a charge generating layer 161 located between the first emission unit 151 and the second emission unit 152 and including an n-type charge generating region 161-N and a p-type charge generating region 161-P.

As used herein, the term “n-type” refers to n-type semiconductor characteristics such as, for example, electron injection characteristics or electron transport characteristics. As used herein, the term “p-type” refers to p-type semiconductor characteristics such as, for example, hole injection characteristics or hole transport characteristics.

The charge generating layer 161 may include the n-type charge generating region 161-N and the p-type charge generating region 161-P. In some embodiments, the n-type charge generating region 161-N and the p-type charge generating region 161-P may directly contact (e.g., physically contact) each other to form an NP junction. Due to the NP junction, electrons and holes may be concurrently (e.g., simultaneously) generated between the n-type charge generating region 161-N and the p-type charge generating region 161-P. The generated electrons are transferred to one of two adjacent emission units through the n-type charge generating region 161-N. The generated holes are transferred to the other emission unit among the two adjacent emission units through the p-type charge generating region 161-P. In addition, because the charge generating layer 161 includes one n-type charge generating region 161-N and one p-type charge generating region 161-P, the organic light-emitting device 10 including one charge generating layer 161 includes one n-type charge generating region 161-N and one p-type charge generating region 161-P.

The n-type charge generating region 161-N supplies electrons to the first emission unit 151 adjacent to the first electrode 110, and the p-type charge generating region 161-P supplies holes to the second emission unit 152 adjacent to the second electrode 190, thereby further increasing luminescence efficiency of an organic light-emitting device including a plurality of emission layers, and reducing driving voltage of the organic light-emitting device.

The p-type charge generating region 161-P may include a phosphate-containing compound. In the present specification, a phosphate-containing compound refers to a compound containing at least one selected from phosphoric acid (H₃PO₄), a dihydrogen phosphate ion (H₂PO₄ ⁻), a hydrogen phosphate ion (HPO₄ ²⁻), a phosphate ion (PO₄ ³⁻), and a pyrophosphate ion (P₂O₇ ⁴⁻). In addition, in the present specification, a phosphate-containing compound may include a hydrate of a compound containing at least one selected from the dihydrogen phosphate ion (H₂PO₄ ⁻), the hydrogen phosphate ion (HPO₄ ²⁻), the phosphate ion (PO₄ ³⁻), and the pyrophosphate ion (P₂O₇ ⁴⁻), as described above.

The phosphate-containing compound may be at least one selected from phosphoric acid (H₃PO₄), an alkali metal phosphate, an alkaline earth metal phosphate, a transition metal phosphate, a post-transition metal phosphate, a lanthanide metal phosphate, an actinide metal phosphate, a metalloid phosphate, an ammonium phosphate, a transition metal ammonium phosphate, and hydrates of any one of the aforementioned.

The alkali metal may be selected from lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).

The alkaline earth metal may be selected from magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

The transition metal may be selected from scandium (Sc), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), and silver (Ag).

The post-transition metal may be selected from aluminum (Al), gallium (Ga), cadmium (Cd), indium (In), mercury (Hg), thallium (TI), lead (Pb), and bismuth (Bi).

The lanthanide metal may be selected from lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), erbium (Er), and thulium (Tm).

The actinide metal may be selected from thorium (Th) and uranium (U).

The metalloid may be selected from boron (B) and antimony (Sb).

For example, the phosphate-containing compound may be at least one selected from H₃PO₄, Ag₃PO₄, Ba(PO₃)₂, AlPO₄, BPO₄, Ba₂P₂O₇, Ba₃(PO₄)₂, BiPO₄, CaHPO₄, Ca₃(PO₄)₂, Ca₄(PO₄)₂O, Cd₃(PO₄)₂, CePO₄, Co₃(PO₄)₂, CrPO₄, CsH₂PO₄, Cs₂HPO₄, Cs₂PO₄, Cs₃PO₄, Cu₃(PO₄)₂, ErPO₄, FeO₈H₄P₂, FePO₄, Fe₄(P₂O₇)₃, GaPO₄, Hg₃(PO₄)₂, InPO₄, K₂HPO₄, KH₂PO₄, LaPO₄, LaPO₄.5H₂O, LiH₂PO₄, Li₂HPO₄, Li₃PO₄, Mn₃(PO₄)₂, MgHPO₄, MgNH₄PO₄.6H₂O, Mg₂P₂O₇, (NH₄)₃PO₄, NaH₂PO₄, Na₂PO₄, NdPO₄, Ni₃(PO₄)₂, Pb₃(PO₄)₃, PrPO₄, RbH₂PO₄, Rb₂HPO₄, Rb₃PO₄, SbPO₄, ScPO₄, Sr₃(PO₄)₂, Th₃(PO₄)₄, TI₃PO₄, TmPO₄, U(PO₄)₂, YPO₄, Zn₂P₂O₇, Zn₃(PO₄)₂, Zr₃(PO₄)₄, and Bi₃PO₄.

For example, the phosphate-containing compound may be BiPO₄, but embodiments of the present disclosure are not limited thereto.

In one embodiment, at least one of the m−1 p-type charge generating regions 161-P may include at least one of a p-type charge generating layer and an interlayer. For example, at least one of the m−1 p-type charge generating regions 161-P may include only a p-type charge generating layer (e.g., a sole p-type charge generating layer), may include only an interlayer (e.g., a sole interlayer), or may include both a p-type charge generating layer and an interlayer.

For example, at least one of the m−1 p-type charge generating regions 161-P may include a p-type charge generating layer, and the p-type charge generating layer may include the phosphate-containing compound.

In one embodiment, at least one of the m−1 p-type charge generating regions may include a p-type charge generating layer, and the p-type charge generating layer may include the phosphate-containing compound and a hole transport material. For example, the p-type charge generating layer may include the phosphate-containing compound in an amount of about 0.01 parts by weight to about 49.99 parts by weight based on 100 parts by weight of the hole transport material. For example, the p-type charge generating layer may include the phosphate-containing compound in an amount of about 0.1 parts by weight to about 49.9 parts by weight, for example, about 1 parts by weight to about 20 parts by weight or about 5 parts by weight to about 20 parts by weight, based on 100 parts by weight of the hole transport material.

An amount of the phosphate-containing compound may be, for example, about 0.01 parts by weight to about 49.99 parts by weight based on the total weight of a material constituting a p-type charge generating layer.

The hole transport material is not particularly limited as long as the hole transport material is a material having hole transport characteristics, and may include, for example, an organic or inorganic material having hole transport characteristics. For example, the hole transport material may be selected from compounds represented by Formulae 201, 202, and 301-2 below:

In Formulae 201, 202, and 301-2,

A₃₀₁ to A₃₀₄ may each independently be selected from a benzene ring, a naphthalene ring, a phenanthrene ring, a fluoranthene ring, a triphenylene ring, a pyrene ring, a chrysene ring, a pyridine ring, a pyrimidine ring, an indene ring, a fluorene ring, a spiro-bifluorene ring, a benzofluorene ring, a dibenzofluorene ring, an indole ring, a carbazole ring, a benzocarbazole ring, a dibenzocarbazole ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a naphthofuran ring, a benzonaphthofuran ring, a dinaphthofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a naphthothiophene ring, a benzonaphthothiophene ring, and a dinaphthothiophene ring,

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄],

L₂₀₁ to L₂₀₄ and L₃₀₁ to L₃₀₃ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted or unsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstituted C₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer from 0 to 3,

xa5 may be an integer from 1 to 10,

xb1 to xb4 may each independently be an integer from 0 to 5,

xb22 and xb23 may each independently be 0, 1, or 2,

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,

R₃₀₁ to R₃₀₄ may each independently be selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁ to Q₃₃ and Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one embodiment, the m−1 n-type charge generating layers may include a material that may be included in an electron transport region which will be described later.

A thickness of the p-type charge generating layer may be in a range from about 10 Å to about 500 Å, for example, from about 20 Å to about 300 Å, but embodiments of the present disclosure are not limited thereto. When the thickness of the p-type charge generating layer is within the foregoing range, a high-quality organic light-emitting device may be embodied without a substantial increase in driving voltage.

In one embodiment, at least one of the m−1 p-type charge generating regions 161-P may include an interlayer, and the interlayer may include the phosphate-containing compound.

For example, the interlayer may include (or consist of) a phosphate-containing compound. As another example, the interlayer may include a phosphate-containing compound and may further include an alkali metal, an alkaline earth metal, a rare earth metal, a transition metal, a post-transition metal, and a metalloid, or any combination thereof.

In one embodiment, the interlayer may include (or consist of) the phosphate-containing compound.

In one or more embodiments, at least one of the m−1 p-type charge generating regions 161-P may include a p-type charge generating layer and an interlayer, and the interlayer may be located between the n-type charge generating region 161-N and the p-type charge generating layer.

The interlayer may directly contact (e.g., physically contact) the p-type charge generating layer and the n-type charge generating region 161-N. In one embodiment, the interlayer may be present at an interface between the n-type charge generating region 161-N and the p-type charge generating layer.

The interlayer may be located between an n-type charge generating region and a p-type charge generating region, and thus, a fermi level alignment barrier may be lowered in a charge generating layer at which an NP junction is formed. For example, when the interlayer is present at an interface between the p-type charge generating layer and the n-type charge generating region, a barrier between the n-type charge generating region and the p-type charge generating layer may be lowered, thereby efficiently generating charges.

In one embodiment, at least one of the p-type charge generating layer and the interlayer may include a phosphate-containing compound.

In one embodiment, the p-type charge generating layer may include a phosphate-free compound and may not include a phosphate-containing compound, and the interlayer may include the phosphate-containing compound. For example, the p-type charge generating layer may be substantially free of phosphate and/or a phosphate-containing compound, such that the phosphate and/or phosphate-containing compound is only present in the p-type charge generating layer, if at all, as an incidental impurity. In some embodiments, the p-type charge generating layer is free (e.g., completely free) of the phosphate and/or phosphate-containing compound.

In one or more embodiments, both the p-type charge generating layer and the interlayer may include a phosphate-containing compound. For example, the p-type charge generating layer may include the phosphate-containing compound and a hole transport material, and the interlayer may include (or consist of) the phosphate-containing compound.

A thickness of the interlayer may be from about 1 Å to about 3,000 Å, for example, from about 10 Å to about 1,000 Å or from about 50 Å to about 100 Å.

The organic light-emitting device according to the present disclosure includes a phosphate-containing compound which is a semiconductor material having a deep lowest unoccupied molecular orbital (LUMO) energy level and a large energy band gap in a p-type charge generating layer and/or an interlayer, thereby efficiently generating charges by adjusting a barrier between a p-type charge generating region and an n-type charge generating region, and accordingly, a high-quality organic light-emitting device may be embodied.

In addition, the organic light-emitting device may include the phosphate-containing compound in a single-layered form in a p-type charge generating layer and/or an interlayer, or may include the phosphate-containing compound in a form of a dopant along with the hole transport material in the p-type charge generating layer and/or the interlayer.

When a phosphate-containing compound is included in a form doped with a hole transport material as described above, electrical conductivity of a charge generating layer is increased such that charges are efficiently generated and hole transport to an adjacent emission unit is further facilitated, and thus, an organic light-emitting device including the charge generating layer may have improved efficiency.

In one embodiment, the m−1 n-type charge generating regions 161-N may include a metal-free compound including at least one π-electron-deficient nitrogen-containing ring, a metal-containing material, or any combination thereof. The metal-containing material may include a metal, a metal complex, or any combination thereof.

When the m−1 n-type charge generating regions 161-N include a metal as the metal-containing material, the metal may include an alkali metal, an alkaline earth metal, a rare earth metal, or any combination thereof. For example, when the m−1 n-type charge generating regions 161-N include a metal as the metal-containing material, the metal may include at least one selected from Li, Na, K, Rb, Cs, Mg, Ca, Ce, Nd, Sm, Eu, Tb, Th, Yb, Lu, and Y. In one embodiment, when at least one of the m−1 n-type charge generating regions includes a metal as the metal-containing material, the metal may be Yb, but embodiments of the present disclosure are not limited thereto.

When at least one of the m−1 n-type charge generating regions includes a metal complex as the metal-containing material, the metal complex may include an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, a transition metal complex, a post-transition metal complex, or any combination thereof. For example, when at least one of the m−1 n-type charge generating regions includes a metal complex as the metal-containing material, a metal of the metal complex may be selected from Li, Al, Ti, Zr, Hf, Zn, and Cu. In one embodiment, when at least one of the m−1 n-type charge generating regions includes a metal complex as the metal-containing material, the metal complex may be a Li complex or an Al complex, but embodiments of the present disclosure are not limited thereto.

When at least one of the m−1 n-type charge generating regions includes a metal complex as the metal-containing material, the metal complex may include at least one organic ligand selected from hydroxyquinoline, hydroxyisoquinoline, hydroxybenzoquinoline, hydroxyacridine, hydroxyphenanthridine, hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxydiphenyloxadiazole, hydroxydiphenylthiadiazole, hydroxyphenylpyridine, hydroxyphenylbenzoimidazole, hydroxyphenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene. For example, when at least one of the m−1 n-type charge generating regions 161-N includes a metal complex as the metal-containing material, the metal complex may include at least one organic ligand selected from substituted or unsubstituted hydroxyquinoline and substituted or unsubstituted hydroxyphenylbenzothiazole. The metal complex may be lithium quinolate (Liq) or aluminum quinolate (Alq₃), but embodiments of the present disclosure are not limited thereto.

For example, the m−1 n-type charge generating regions 161-N may include a compound represented by Formula 601, a metal, a metal complex, or any combination thereof:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21).  Formula 601

In Formula 601,

Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xe11 may be 1, 2, or 3,

L₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xe1 may be an integer from 0 to 5,

R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and

xe21 may be an integer from 1 to 5.

A thickness of the n-type charge generating region may be in a range from about 10 Å to about 500 Å. For example, a thickness of the n-type charge generating region 161-N may be in a range from about 20 Å to about 300 Å, but embodiments of the present disclosure are not limited thereto. When the thickness of the n-type charge generating region 161-N is within the foregoing range, a high-quality organic light-emitting device may be embodied without a substantial increase in driving voltage.

FIG. 2 is a schematic cross-sectional view of an organic light-emitting device according to another embodiment.

As in FIG. 1, the organic light-emitting device 20 of FIG. 2 includes a first electrode 110, a second electrode 190 facing the first electrode 110, a first emission unit 151 between the first electrode 110 and the second electrode 190, a second emission unit 152 between the first emission unit 151 and the second electrode 190, and a charge generating layer 161 between the first emission unit 151 and the second emission unit 152. The charge generating layer 161 includes an n-type charge generating region 161-N, a p-type charge generating layer 161-P−1, and an interlayer 161-IL between the n-type charge generating region 161-N and the p-type charge generating layer 161-P−1.

In the organic light-emitting device 20, the first electrode 110, the first emission unit 151, the n-type charge generating region 161-N, the interlayer 161-IL, the p-type charge generating layer 161-P−1, the second emission unit 152, and the second electrode 190 are the same as described above.

FIG. 2 illustrates an embodiment where a p-type charge generating region includes both the p-type charge generating layer 161-P−1 and the interlayer 161-IL, but the present disclosure is not limited thereto, and the p-type charge generating region may include only one of the p-type charge generating layer 161-P−1 or the interlayer 161-IL.

FIG. 3 is a schematic cross-sectional view of an organic light-emitting device according to an embodiment. In the organic light-emitting device 30 according to an embodiment, m is 3. For example, in some embodiments, the organic light-emitting device 30 includes three emission units that are a first emission unit 151, a second emission unit 152, and a third emission unit 153.

The organic light-emitting device 30 includes: a first electrode 110; a second electrode 190 facing the first electrode 110; the first emission unit 151, the second emission unit 152, and the third emission unit 153 that are located between the first electrode 110 and the second electrode 190 and sequentially stacked from the first electrode 110; a first charge generating layer 161 between the first emission unit 151 and the second emission unit 152; and a second charge generating layer 162 between the second emission unit 152 and the third emission unit 153, wherein the first charge generating layer 161 includes a first n-type charge generating region 161-N and a first p-type charge generating region 161-P, and the second charge generating layer 162 includes a second n-type charge generating region 162-N and a second p-type charge generating region 162-P.

The first n-type charge generating region 161-N may be located between the first electrode 110 and the first p-type charge generating region 161-P, and the second n-type charge generating region 162-N may be located between the first electrode 110 and the second p-type charge generating region 162-P.

The first n-type charge generating region 161-N and the second n-type charge generating region 162-N may be the same as described in connection with the n-type charge generating region.

The first p-type charge generating region 161-P and the second p-type charge generating region 162-P may be the same as described in connection with the p-type charge generating region.

At least one of the first p-type charge generating region 161-P and the second p-type charge generating region 162-P may include the phosphate-containing compound. For example, the first p-type charge generating region 161-P and the second p-type charge generating region 162-P may include the phosphate-containing compound.

In one embodiment, the first p-type charge generating region 161-P and the second p-type charge generating region 162-P may include at least one of a p-type charge generating layer and an interlayer. For example, the first p-type charge generating region 161-P may include a first p-type charge generating layer and a first interlayer, and the second p-type charge generating region 162-P may include a second p-type charge generating layer and a second interlayer.

Accordingly, as illustrated in FIG. 4, an organic light-emitting device 40 according to an embodiment includes: a first electrode 110; a second electrode 190 facing the first electrode 110; a first emission unit 151, a second emission unit 152, and a third emission unit 153 that are located between the first electrode 110 and the second electrode 190 and sequentially stacked from the first electrode 110; a first charge generating layer 161 between the first emission unit 151 and the second emission unit 152; and a second charge generating layer 162 between the second emission unit 152 and the third emission unit 153, wherein the first charge generating layer 161 includes a first n-type charge generating region 161-N, a first p-type charge generating layer 161-P−1, and a first interlayer 161-IL between the first n-type charge generating region 161-N and the first p-type charge generating layer 161-P−1, and the second charge generating layer 162 includes a second n-type charge generating region 162-N, a second p-type charge generating layer 162-P−1, and a second interlayer 162-IL between the second n-type charge generating region 162-N and the second p-type charge generating layer 162-P−1.

In the organic light-emitting device 40, the first electrode 110, the first emission unit 151, the n-type charge generating regions 161-N and 162-N, the interlayers 161-IL and 162-IL, the p-type charge generating layers 161-P−1 and 162-P−1, the second emission unit 152, the third emission unit 153, and the second electrode 190 are the same as described above.

FIG. 4 illustrates an embodiment where the p-type charge generating regions respectively include both the p-type charge generating layer 161-P−1 and the interlayer 161-IL and both the p-type charge generating layer 162-P−1 and the interlayer 162-IL, but the present disclosure is not limited thereto, and the p-type charge generating regions may respectively include only one of the p-type charge generating layer 161-P−1 or the interlayer 161-IL and only one of the p-type charge generating layer 162-P−1 or the interlayer 162-IL.

According to another aspect of an embodiment, there may be provided an organic light-emitting device including: a first electrode; a second electrode facing the first electrode; m emission units stacked between the first electrode and the second electrode and including at least one emission layer; and m−1 charge generating layers located between two adjacent emission units among the m emission units, each of the charge generating layers including one n-type charge generating region and one p-type charge generating region, wherein m is an integer of 2 or more, at least one of the m emission units further includes a hole transport region between the first electrode and the emission layer, and at least one of the p-type charge generating region and the hole transport region includes a phosphate-containing compound.

The first electrode, the second electrode, the emission unit, and the charge generating layer are the same as described above, and the hole transport region is the same as described below.

For example, the hole transport region may be located between at least one p-type charge generating region among the m−1 p-type charge generating regions and an emission layer included in an adjacent emission unit.

In one embodiment, the hole transport region may include a first hole transport layer and a second hole transport layer, the first hole transport layer may be located between the first electrode and the second hole transport layer, the first hole transport layer may include a p-dopant, and at least one of the p-type charge generating region and the first hole transport layer may include a phosphate-containing compound.

In one or more embodiments, the p-type charge generating region may include at least one of a p-type charge generating layer and an interlayer, the hole transport region may include a first hole transport layer and a second hole transport layer, the first hole transport layer may be located between the first electrode and the second hole transport layer, the first hole transport layer may include a p-dopant, and at least one of the p-type charge generating layer, the interlayer, and the first hole transport layer may include a phosphate-containing compound.

The p-dopant is the same as described below.

In one embodiment, the hole transport region may be located between at least one p-type charge generating region among the m−1 p-type charge generating regions and an emission layer included in an adjacent emission unit, the hole transport region may include a first hole transport layer and a second hole transport layer, the first hole transport layer may be located between the first electrode and the second hole transport layer, and the first hole transport layer may include a p-dopant. In some embodiments, at least one of the p-type charge generating region and the first hole transport layer may include a phosphate-containing compound.

In one embodiment, the p-type charge generating region may directly contact (e.g., physically contact) the first hole transport layer.

In one embodiment, the p-type charge generating region may include a p-type charge generating layer, and at least one of the p-type charge generating layer and the first hole transport layer may include a phosphate-containing compound.

In one or more embodiments, the p-type charge generating region may include a p-type charge generating layer and an interlayer, and at least one of the p-type charge generating layer, the interlayer, and the first hole transport layer may include a phosphate-containing compound.

When a first hole transport layer including a p-dopant is located on the p-type charge generating region, holes generated in the p-type charge generating region may be efficiently transferred to an adjacent emission unit.

The term “an organic layer,” as used herein, refers to a single layer and/or a plurality of layers located between the first electrode and the second electrode of an organic light-emitting device. A material included in the “organic layer” is not limited to an organic material. For example, the organic layer may include an inorganic material.

Hereinafter, a structure of each of the organic light-emitting devices 10, 20, 30, and 40 according to embodiments and a method of manufacturing the same will be further described in connection with FIGS. 1 to 4.

First Electrode 110

In FIGS. 1 to 4, a substrate may be additionally located under the first electrode 110 or above the second electrode 190. The substrate may be a glass substrate and/or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/or water resistance.

The first electrode 110 may be formed by depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, the material for forming the first electrode 110 may be selected from materials having a high work function to facilitate hole injection.

The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode 110 is a transmissive electrode, a material for forming the first electrode 110 may be selected from indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), and any combination thereof, but embodiments of the present disclosure are not limited thereto. In one or more embodiments, when the first electrode 110 is a semi-transmissive electrode or a reflective electrode, a material for forming the first electrode 110 may be selected from magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg-ln), magnesium-silver (Mg—Ag), and any combination thereof, but embodiments of the present disclosure are not limited thereto.

The first electrode 110 may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode 110 is not limited thereto.

Emission Units 151, 152, and 153

Emission units 151, 152, and 153 may be located on the first electrode 110. FIGS. 1 and 2 each illustrate an organic light-emitting device including emission units 151 and 152, and FIGS. 3 and 4 each illustrate an organic light-emitting device including emission units 151, 152, and 153. In the drawings, organic light-emitting devices each having two or three emission units are illustrated, but the number of emission units of the organic light-emitting device of the present disclosure is not limited thereto and may be four or more as necessary or desired.

The organic light-emitting devices 10, 20, 30, and 40 may each further include a hole transport region between the first electrode 110 and the emission units 151, 152, and 153 and an electron transport region between the emission units 151, 152, and 153 and the second electrode 190.

Hole Transport Region

The hole transport region may have i) a single-layered structure including (e.g., consisting of) a single layer consisting of a single material, ii) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including (e.g., consisting of) a plurality of different materials.

The hole transport region may include at least one layer selected from a hole injection layer, a hole transport layer, an emission auxiliary layer, and an electron blocking layer.

For example, the hole transport region may have a single-layered structure including a single layer including a plurality of different materials or a multi-layered structure having a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole transport layer/emission auxiliary layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, wherein for each structure, constituting layers are sequentially stacked from the first electrode 110 in this stated order, but the structure of the hole transport region is not limited thereto.

The hole transport region may include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB(NPD), (3-NPB, TPD, spiro-TPD, spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted or unsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstituted C₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer from 0 to 3,

xa5 may be an integer from 1 to 10, and

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

For example, in Formula 202, R₂₀₁ and R₂₀₂ may optionally be linked to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group, and R₂₀₃ and R₂₀₄ may optionally be linked to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

In one embodiment, in Formulae 201 and 202,

L₂₀₁ to L₂₀₅ may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, and a pyridinylene group; and

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, and a pyridinylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, —Si(Q₃₁)(Q₃₂)(Q₃) and —N(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one or more embodiments, xa1 to xa4 may each independently be 0, 1, or 2.

In one or more embodiments, xa5 may be 1, 2, 3, or 4.

In one or more embodiments, R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from: a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ are the same as described in the present specification.

In one or more embodiments, at least one of R₂₀₁ to R₂₀₃ in Formula 201 may each independently be selected from:

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; and

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formula 202, i) R₂₀₁ and R₂₀₂ may be linked to each other via a single bond, and/or ii) R₂₀₃ and R₂₀₄ may be linked to each other via a single bond.

In one or more embodiments, at least one of R₂₀₁ to R₂₀₄ in Formula 202 may each independently be selected from:

a carbazolyl group; and

a carbazolyl group substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

but embodiments of the present disclosure are not limited thereto.

The compound represented by Formula 201 may be represented by Formula 201-1 below:

In one embodiment, the compound represented by Formula 201 may be represented by Formula 201-2 below, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201-2(1) below, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A below:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A(1) below, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A-1 below, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 202 may be represented by Formula 202-1 below:

In one or more embodiments, the compound represented by Formula 202 may be represented by Formula 202-1(1) below:

In one embodiment, the compound represented by Formula 202 may be represented by Formula 202A below:

In one or more embodiments, the compound represented by Formula 202 may be represented by Formula 202A-1 below:

In Formulae 201-1, 201-2, 201-2(1), 201A, 201A(1), 201A-1,202-1, 202-1(1), 202A, and 202A-1,

L₂₀₁ to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ are the same as described in the present specification,

L₂₀₅ may be selected from a phenylene group and a fluorenylene group,

X₂₁₁ may be selected from O, S, and N(R₂₁₁),

X₂₁₂ may be selected from O, S, and N(R₂₁₂),

R₂₁₁ and R₂₁₂ are the same as described in connection with R₂₀₃, and

R₂₁₃ to R₂₁₇ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group.

The hole transport region may include at least one compound selected from Compounds HT1 to HT48, but embodiments of the present disclosure are not limited thereto:

A thickness of the hole transport region may be in a range from about 100 Å to about 10,000 Å, for example, from about 100 Å to about 1,000 Å. When the hole transport region includes at least one of a hole injection layer and a hole transport layer, a thickness of the hole injection layer may be in a range from about 100 Å to about 9,000 Å, for example, from about 100 Å to about 1,000 Å, and a thickness of the hole transport layer may be in a range from about 50 Å to about 2,000 Å, for example, from about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, suitable or satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by an emission layer, and the electron blocking layer may block or reduce the flow of electrons from an electron transport region. The emission auxiliary layer and the electron blocking layer may include the materials as described above.

p-Dopant

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant.

In one embodiment, a lowest unoccupied molecular orbital (LUMO) energy level of the p-dopant may be −3.5 eV or less.

The p-dopant may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the p-dopant may include at least one selected from:

a quinone derivative, such as tetracyanoquinodimethane (TCNQ) or 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);

a metal oxide, such as tungsten oxide or molybdenum oxide;

1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and

a compound represented by Formula 221 below,

but embodiments of the present disclosure are not limited thereto:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and at least one selected from R₂₂₁ to R₂₂₃ may have at least one substituent selected from a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀ alkyl group substituted with —F, a C₁-C₂₀ alkyl group substituted with —Cl, a C₁-C₂₀ alkyl group substituted with —Br, and a C₁-C₂₀ alkyl group substituted with —I.

Emission Layers in Emission Units 151, 152, and 153

The emission units 151, 152, and 153 of the organic light-emitting devices 10, 20, 30, and 40 may each include an emission layer, and the emission layer may have a structure in which two or more layers selected from among a red emission layer, a green emission layer, a yellow emission layer, and a blue emission layer are in contact (e.g., physical contact) with each other or spaced apart from each other, and/or may have a structure in which two or more layers selected from among a red light emission material, a green light emission material, a yellow light emission material, and a blue light emission material are mixed in a single layer.

The emission layer may further include an electron transport auxiliary layer formed on the emission layer and/or a hole transport auxiliary layer formed under the emission layer. The hole transport auxiliary layer may act as the hole transport layer, the emission auxiliary layer, and the electron blocking layer, and the electron transport auxiliary layer may act as a buffer layer, a hole blocking layer, an electron control layer, and an electron transport layer, which will be further described herein below. Materials that may be used for the hole transport auxiliary layer and the electron transport auxiliary layer may be the same as described in connection with the hole transport region and an electron transport region which will be further described herein below.

The emission layer may include a host and a dopant. The dopant may include at least one selected from a phosphorescent dopant and a fluorescent dopant.

An amount of a dopant in the emission layer may be, based on about 100 parts by weight of the host, in a range from about 0.01 parts by weight to about 15 parts by weight, but embodiments of the present disclosure are not limited thereto.

A thickness of the emission layer may be in a range from about 100 Å to about 1,000 Å, for example, from about 200 Å to about 600 Å. When the thickness of the emission layer is within this range, excellent luminescence characteristics may be obtained without a substantial increase in driving voltage.

Host in Emission Layer

In one or more embodiments, the host may include a compound represented by Formula 301 below.

[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21).  Formula 301

In Formula 301,

Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xb11 may be 1, 2, or 3,

L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xb1 may be an integer from 0 to 5,

R₃₀₁ may be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(G₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂), and

xb21 may be an integer from 1 to 5,

wherein Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, but embodiments of the present disclosure are not limited thereto.

In one embodiment, Ar₃₀₁ in Formula 301 may be selected from:

a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, and a dibenzothiophene group; and

a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, and a dibenzothiophene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, but embodiments of the present disclosure are not limited thereto.

When xb11 in Formula 301 is 2 or more, two or more of Ar₃₀₁(s) may be linked to each other via a single bond.

In one or more embodiments, the compound represented by Formula 301 may be represented by Formula 301-1 or 301-2:

In Formulae 301-1 and 301-2,

A301 to A304 may each independently be selected from a benzene ring, a naphthalene ring, a phenanthrene ring, a fluoranthene ring, a triphenylene ring, a pyrene ring, a chrysene ring, a pyridine ring, a pyrimidine ring, an indene ring, a fluorene ring, a spiro-bifluorene ring, a benzofluorene ring, a dibenzofluorene ring, an indole ring, a carbazole ring, a benzocarbazole ring, a dibenzocarbazole ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a naphthofuran ring, a benzonaphthofuran ring, a dinaphthofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a naphthothiophene ring, a benzonaphthothiophene ring, and a dinaphthothiophene ring,

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄],

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, R₃₀₁, and Q₃₁ to Q₃₃ may be the same as described above,

L₃₀₂ to L₃₀₄ may each independently be the same as described in connection with L₃₀₁,

xb2 to xb4 may each independently be the same as described in connection with xb1, and

R₃₀₂ to R₃₀₄ may each independently be the same as described in connection with R₃₀₁.

For example, L₃₀₁ to L₃₀₄ in Formulae 301, 301-1, and 301-2 may each independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, a pyridinylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a thiadiazolylene group, an oxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a triazinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, a pyridinylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a thiadiazolylene group, an oxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a triazinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group, and an azacarbazolylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may be the same as described above.

In one embodiment, R₃₀₁ to R₃₀₄ in Formulae 301, 301-1, and 301-2 may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ are the same as described above.

In one or more embodiments, the host may include a Be complex, an alkaline earth metal complex, or any combination thereof. For example, the host may be selected from a Be complex (for example, Compound H55), an Mg complex, and a Zn complex.

The host may include at least one selected from 9,10-di(2-naphthyl)anthracene (ADN), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), 9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene (mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and at least one selected from Compounds H1 to H55, but embodiments of the present disclosure are not limited thereto:

Phosphorescent Dopant Included in Emission Layer

The phosphorescent dopant may include an organometallic complex represented by Formula 401 below:

In Formulae 401 and 402,

M may be selected from iridium (Ir), platinum (Pt), palladium (Pd), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), rhodium (Rh), and thulium (Tm),

L₄₀₁ may be selected from ligands represented by Formula 402, and xc1 may be 1, 2, or 3, wherein, when xc1 is 2 or more, two or more of L₄₀₁(s) may be identical to or different from each other,

L₄₀₂ may be an organic ligand, and xc2 may be an integer from 0 to 4, wherein, when xc2 is 2 or more, two or more of L₄₀₂(s) may be identical to or different from each other,

X₄₀₁ to X₄₀₄ may each independently be nitrogen or carbon,

X₄₀₁ and X₄₀₃ may be linked via a single bond or a double bond, and X₄₀₂ and X₄₀₄ may be linked via a single bond or a double bond,

A₄₀₁ and A₄₀₂ may each independently be a C₅-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,

X₄₀₅ may be a single bond, *—C(═O)—*′, *—N(Q₄₁₁)-*′, *—C(Q₄₁₁)(Q₄₁₂)-*′, *—C(Q₄₁₁)=C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *═C(Q₄₁₁)=*′, wherein Q₄₁₁ and Q₄₁₂ may be hydrogen, deuterium, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group,

X₄₀₆ may be a single bond, O, or S,

R₄₀₁ and R₄₀₂ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂), and Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a C₆-C₂₀ aryl group, and a C₁-C₂₀ heteroaryl group,

xc11 and xc12 may each independently be an integer from 0 to 10, and

* and *′ in Formula 402 each indicate a binding site to M in Formula 401.

In one embodiment, A₄₀₁ and A₄₀₂ in Formula 402 may each independently be selected from a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, an indene group, a pyrrole group, a thiophene group, a furan group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a quinoxaline group, a quinazoline group, a carbazole group, a benzimidazole group, a benzofuran group, a benzothiophene group, an isobenzothiophene group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a dibenzofuran group, and a dibenzothiophene group.

In one or more embodiments, in Formula 402, i) X₄₀₁ may be nitrogen, and X₄₀₂ may be carbon, or ii) each of X₄₀₁ and X₄₀₂ may be nitrogen.

In one or more embodiments, R₄₀₁ and R₄₀₂ in Formula 402 may each independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a phenyl group, a naphthyl group, a cyclopentyl group, a cyclohexyl group, an adamantly group, a norbornanyl group, and a norbornenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantly group, a norbornanyl group, a norbornenyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantly group, a norbornanyl group, a norbornenyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, an adamantly group, a norbornanyl group, a norbornenyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; and

—Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂),

wherein Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, and a naphthyl group, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, when xc1 in Formula 401 is 2 or more, two A₄₀₁(s) in two or more of L₄₀₁(s) may optionally be linked to each other via X₄₀₇, which is a linking group, two A₄₀₂(s) may optionally be linked to each other via X₄₀₈, which is a linking group (see Compounds PD1 to PD4 and PD7). X₄₀₇ and X₄₀₈ may each independently be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₃)-*′, *—C(Q₄₁₃)(Q₄₁₄)-*′, or *—C(Q₄₁₃)═C(Q₄₁₄)-*′ (where Q₄₁₃ and Q₄₁₄ may each independently be hydrogen, deuterium, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group), but embodiments of the present disclosure are not limited thereto.

L₄₀₂ in Formula 401 may be a monovalent, divalent, or trivalent organic ligand. For example, L₄₀₂ may be selected from halogen, diketone (for example, acetylacetonate), carboxylic acid (for example, picolinate), —C(═O), isonitrile, —CN, and phosphorus (for example, phosphine or phosphite), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the phosphorescent dopant may be selected from, for example, Compounds PD1 to PD25, but embodiments of the present disclosure are not limited thereto:

Fluorescent Dopant in Emission Layer

The fluorescent dopant may include an arylamine compound or a styrylamine compound.

The fluorescent dopant may include a compound represented by Formula 501 below:

In Formula 501,

Ar₅₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group,

L₅₀₁ to L₅₀₃ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xd1 to xd3 may each independently be an integer from 0 to 3,

R₅₀₁ and R₅₀₂ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and

xd4 may be an integer from 1 to 6.

In one embodiment, Ar₅₀₁ in Formula 501 may be selected from:

a naphthalene group, a heptalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, and an indenophenanthrene group; and

a naphthalene group, a heptalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, and an indenophenanthrene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one or more embodiments, L₅₀₁ to L₅₀₃ in Formula 501 may each independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, and a pyridinylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, and a pyridinylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group.

In one or more embodiments, R₅₀₁ and R₅₀₂ in Formula 501 may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, and —Si(Q₃₁)(Q₃₂)(Q₃₃),

wherein Q₃₁ to Q₃₃ may be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one or more embodiments, xd4 in Formula 501 may be 2, but embodiments of the present disclosure are not limited thereto.

For example, the fluorescent dopant may be selected from Compounds FD1 to FD22:

In one or more embodiments, the fluorescent dopant may be selected from the following compounds, but embodiments of the present disclosure are not limited thereto.

Electron Transport Region

The electron transport region may have i) a single-layered structure including (e.g., consisting of) a single layer consisting of a single material, ii) a single-layered structure including (consisting of) a single layer including (e.g., consisting of) a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including (e.g., consisting of) a plurality of different materials.

The electron transport region may include at least one selected from a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, and an electron injection layer, but embodiments of the present disclosure are not limited thereto.

For example, the electron transport region may have an electron transport layer/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, wherein for each structure, constituting layers are sequentially stacked from an emission layer. However, embodiments of the structure of the electron transport region are not limited thereto.

The electron transport region (for example, a buffer layer, a hole blocking layer, an electron control layer, and/or an electron transport layer in the electron transport region) may include a metal-free compound containing at least one π-electron-deficient nitrogen-containing ring.

As used herein, the term “π-electron-deficient nitrogen-containing ring” indicates a C₁-C₆₀ heterocyclic group having at least one *—N=*′ moiety as a ring-forming moiety.

For example, the “π-electron-deficient nitrogen-containing ring” may be i) a 5-membered to 7-membered heteromonocyclic group having at least one *—N=*′ moiety, ii) a heteropolycyclic group in which two or more 5-membered to 7-membered heteromonocyclic groups each having at least one *—N=*′ moiety are condensed with each other (e.g., condensed together), or iii) a heteropolycyclic group in which at least one of 5-membered to 7-membered heteromonocyclic groups, each having at least one *—N=*′ moiety, is condensed with (e.g., combined with) at least one C₅-C₆₀ carbocyclic group.

Examples of the π-electron-deficient nitrogen-containing ring include an imidazole ring, a pyrazole ring, a thiazole ring, an isothiazole ring, an oxazole ring, an isoxazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, an indazole ring, a purine ring, a quinoline ring, an isoquinoline ring, a benzoquinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinazoline ring, a cinnoline ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a phenazine ring, a benzimidazole ring, an isobenzothiazole ring, a benzoxazole ring, an isobenzoxazole ring, a triazole ring, a tetrazole ring, an oxadiazole ring, a triazine ring, a thiadiazole ring, an imidazopyridine ring, an imidazopyrimidine ring, and an azacarbazole ring, but are not limited thereto.

For example, the electron transport region may include a compound represented by Formula 601 below:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21).  Formula 601

In Formula 601,

Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xe11 may be 1, 2, or 3,

L₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xe1 may be an integer from 0 to 5,

R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and

xe21 may be an integer from 1 to 5.

In one embodiment, at least one of Ar₆₀₁(s) in the number of xe11 and R₆₀₁(s) in the number of xe21 may include the π-electron-deficient nitrogen-containing ring.

In one embodiment, ring Ar₆₀₁ in Formula 601 may be selected from:

a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, and an azacarbazole group; and

a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, and an azacarbazole group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(C₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

When xe11 in Formula 601 is 2 or more, two or more of Ar₆₀₁(s) may be linked to each other via a single bond.

In one or more embodiments, Ar₆₀₁ in Formula 601 may be an anthracene group.

In one or more embodiments, the compound represented by Formula 601 may be represented by Formula 601-1 below:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N or C(R₆₁₆), and at least one of X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ may each independently be the same as described in connection with L₆₀₁,

xe611 to xe613 may each independently be the same as described in connection with xe1,

R₆₁₁ to R₆₁₃ may each independently be the same as described in connection with R₆₀₁, and

R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one embodiment, L₆₀₁ and L₆₁₁ to L₆₁₃ in Formulae 601 and 601-1 may each independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, a pyridinylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a thiadiazolylene group, an oxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a triazinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, a pyridinylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a thiadiazolylene group, an oxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a triazinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group, and an azacarbazolylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group,

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.

In one or more embodiments, R₆₀₁ and R₆₁₁ to R₆₁₃ in Formulae 601 and 601-1 may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group; and

—S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂),

wherein Q₆₀₁ and Q₆₀₂ are the same as described in the present specification.

The electron transport region may include at least one compound selected from Compounds ET1 to ET36, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the electron transport region may include at least one compound selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), and NTAZ.

Thicknesses of the buffer layer, the hole blocking layer, and the electron control layer may each independently be in a range from about 20 Å to about 1,000 Å, for example, from about 30 Å to about 300 Å. When the thicknesses of the buffer layer, the hole blocking layer, and the electron control layer are within these ranges, excellent hole blocking characteristics or excellent electron control characteristics may be obtained without a substantial increase in driving voltage.

A thickness of the electron transport layer may be in a range from about 100 Å to about 1,000 Å, for example, from about 150 Å to about 500 Å. When the thickness of the electron transport layer is within the range described above, the electron transport layer may have suitable or satisfactory electron transport characteristics without a substantial increase in driving voltage.

The electron transport region (for example, the electron transport layer in the electron transport region) may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include at least one selected from an alkali metal complex and an alkaline earth metal complex. A metal ion of the alkali metal complex may be selected from a Li ion, a Na ion, a K ion, a Rb ion, and a Cs ion, and a metal ion of the alkaline earth metal complex may be selected from a Be ion, a Mg ion, a Ca ion, a Sr ion, and a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth metal complex may be selected from a hydroxy quinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxydiphenyloxadiazole, a hydroxydiphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenylbenzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2:

The electron transport region may include an electron injection layer that facilitates electron injection from the second electrode 190. The electron injection layer may directly contact (e.g., physically constant) the second electrode 190.

The electron injection layer may have i) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a single material, ii) a single-layered structure including (e.g., consisting of) a single layer including (e.g., consisting of) a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including (e.g., consisting of) a plurality of different materials.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or any combination thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. In one embodiment, the alkali metal may be Li, Na, or Cs. In one or more embodiments, the alkali metal may be Li or Cs, but embodiments of the present disclosure are not limited thereto.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth metal compound, and the rare earth metal compound may be selected from oxides and halides (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth metal, and the rare earth metal.

The alkali metal compound may be selected from alkali metal oxides, such as Li₂O, Cs₂O, or K₂O, and alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, KI, or RbI. In one embodiment, the alkali metal compound may be selected from LiF, Li₂O, NaF, LiI, NaI, CsI, and KI, but embodiments of the present disclosure are not limited thereto.

The alkaline earth metal compound may be selected from alkaline earth metal oxides, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (0<x<1), and Ba_(x)Ca_(1-x)O (0<x<1). In one embodiment, the alkaline earth metal compound may be selected from BaO, SrO, and CaO, but embodiments of the present disclosure are not limited thereto.

The rare earth metal compound may be selected from YbF₃, ScF₃, Sc₂O₃, Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. In one embodiment, the rare earth metal compound may be selected from YbF₃, ScF₃, TbF₃, YbI₃, ScI₃, and TbI₃, but embodiments of the present disclosure are not limited thereto.

The alkali metal complex, the alkaline earth metal complex, and the rare earth metal complex may include an ion of alkali metal, alkaline earth metal, and rare earth metal as described above, and a ligand coordinated with a metal ion of the alkali metal complex, the alkaline earth metal complex, or the rare earth metal complex may be selected from hydroxyquinoline, hydroxyisoquinoline, hydroxybenzoquinoline, hydroxyacridine, hydroxyphenanthridine, hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxydiphenyloxadiazole, hydroxydiphenylthiadiazole, hydroxyphenylpyridine, hydroxyphenylbenzimidazole, hydroxyphenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

The electron injection layer may include (e.g., consist of) an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or any combination thereof, as described above. In one or more embodiments, the electron injection layer may further include the organic material. When the electron injection layer further includes an organic material, the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, the rare earth metal compound, the alkali metal complex, the alkaline earth metal complex, the rare earth metal complex, or any combination thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range from about 1 Å to about 100 Å, for example, from about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the range described above, the electron injection layer may have suitable or satisfactory electron injection characteristics without a substantial increase in driving voltage.

Second Electrode 190

The second electrode 190 may be a cathode which is an electron injection electrode, and in some embodiments, a material for forming the second electrode 190 may be selected from a metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function.

The second electrode 190 may include at least one selected from lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ITO, and IZO, but embodiments of the present disclosure are not limited thereto. The second electrode 190 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 190 may have a single-layered structure or a multi-layered structure including two or more layers.

In some embodiments, the organic light-emitting devices 10, 20, 30, and 40 may each further include a first capping layer under the first electrode 110 and/or may each further include a second capping layer on the second electrode 190.

Light generated in an emission layer of an organic layer of the organic light-emitting devices 10, 20, 30, and 40 may be extracted toward the outside through the first electrode 110 and the first capping layer, each of which may be a semi-transmissive electrode or a transmissive electrode, or light generated in an emission layer of an organic layer thereof may be extracted toward the outside through the second electrode 190 and the second capping layer, each of which may be a semi-transmissive electrode or a transmissive electrode.

The first capping layer and the second capping layer may increase external luminescence efficiency according to the principle of constructive interference.

The first capping layer and the second capping layer may each independently be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, and/or a composite capping layer including an organic material and an inorganic material.

At least one of the first capping layer and the second capping layer may each independently include at least one material selected from a carbocyclic compound, a heterocyclic compound, an amine-based compound, a porphyrine derivative, a phthalocyanine derivative, a naphthalocyanine derivative, an alkali metal complex, and an alkaline earth metal complex. The carbocyclic compound, the heterocyclic compound, and the amine-based compound may be optionally substituted with a substituent containing at least one element selected from O, N, S, Se, Si, F, Cl, Br, and I. In one embodiment, at least one of the first capping layer and the second capping layer may each independently include an amine-based compound.

In one embodiment, at least one of the first capping layer and the second capping layer may each independently include a compound represented by Formula 201 or a compound represented by Formula 202.

In one or more embodiments, at least one of the first capping layer and the second capping layer may each independently include a compound selected from Compounds HT28 to HT33 that are described above and Compounds CP1 to CP5 that are described below, but embodiments of the present disclosure are not limited thereto.

Hereinbefore, the organic light-emitting device has been described with reference to FIGS. 1 to 4, but embodiments of the present disclosure are not limited thereto.

Layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region may be formed in a set or certain region by using one or more suitable methods selected from vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by vacuum deposition, the deposition may be performed at a deposition temperature of about 100° C. to about 500° C., a vacuum degree of about 10′⁸ torr to about 10′³ torr, and a deposition speed of about 0.01 Å/sec to about 100 Å/sec by taking into consideration a material to be included in a layer to be formed and a structure of a layer to be formed.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by spin coating, the spin coating may be performed at a coating speed of about 2,000 rpm to about 5,000 rpm and at a heat treatment temperature of about 80° C. to 200° C. by taking into consideration a material to be included in a layer to be formed and a structure of a layer to be formed.

General Definition of at Least Some of the Substituents

The term “C₁-C₆₀ alkyl group,” as used herein, refers to a linear or branched aliphatic saturated hydrocarbon monovalent group having 1 to 60 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, and a hexyl group. The term “C₁-C₆₀ alkylene group,” as used herein refers to a divalent group having the same (e.g., substantially the same) structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group,” as used herein, refers to a hydrocarbon group having at least one carbon-carbon double bond at a main chain (e.g., in the middle) or at a terminal end (e.g., the terminus) of the C₂-C₃₀ alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the C₂-C₃₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group,” as used herein, refers to a hydrocarbon group having at least one carbon-carbon triple bond at a main chain (e.g., in the middle) or at a terminal end (e.g., the terminus) of the C₂-C₃₀ alkyl group, and examples thereof include an ethynyl group and a propynyl group. The term “C₂-C₆₀ alkynylene group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group,” as used herein, refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group,” as used herein, refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀ cycloalkylene group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group,” as used herein, refers to a monovalent monocyclic group having at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms, and examples thereof include a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group,” as used herein, refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity (e.g., not aromatic), and examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group,” as used herein, refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one double bond in its ring. Examples of the C₁-C₁₀ heterocycloalkenyl group include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group,” as used herein, refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₆₀ arylene group,” as used herein, refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Examples of the C₆-C₆₀ aryl group include a fluorenyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the two or more rings may be fused to each other (e.g., combined together).

The term “C₁-C₆₀ heteroaryl group,” as used herein, refers to a monovalent group having a heterocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group,” as used herein, refers to a divalent group having a heterocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms. Examples of the C₁-C₆₀ heteroaryl group include a carbazolyl group, pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the two or more rings may be condensed with each other (e.g., combined together).

The term “C₆-C₆₀ aryloxy group,” as used herein, refers to —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and the term “C₆-C₆₀ arylthio group,” as used herein, refers to —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group,” as used herein, refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed with each other (e.g., combined together), only carbon atoms as ring-forming atoms, and non-aromaticity in its entire molecular structure (e.g., the entire structure is not aromatic). An example of the monovalent non-aromatic condensed polycyclic group is a 9,10-dihydroanthracenyl group. The term “divalent non-aromatic condensed polycyclic group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings condensed to each other (e.g., combined together), at least one heteroatom selected from N, O, Si, P, and S, other than carbon atoms, as a ring-forming atom, and non-aromaticity in its entire molecular structure (e.g., the entire structure is not aromatic). An example of the monovalent non-aromatic condensed heteropolycyclic group is a 9,9-dimethyl-9,10-dihydroacridinyl group. The term “divalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a divalent group having the same (e.g., substantially the same) structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group,” as used herein, refers to a monocyclic or polycyclic group that includes only carbon as a ring-forming atom and consists of 5 to 60 carbon atoms. The C₅-C₆₀ carbocyclic group may be an aromatic carbocyclic group or a non-aromatic carbocyclic group. The C₅-C₆₀ carbocyclic group may be a ring, such as benzene, a monovalent group, such as a phenyl group, or a divalent group, such as a phenylene group. In one or more embodiments, depending on the number of substituents connected to the C₅-C₆₀ carbocyclic group, the C₅-C₆₀ carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C₁-C₆₀ heterocyclic group,” as used herein, refers to a group having the same (e.g., substantially the same) structure as the C₅-C₆₀ carbocyclic group, except that as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S is used in addition to carbon (the number of carbon atoms may be in a range of 1 to 60).

In the present specification, at least one substituent of the substituted C₅-C₆₀ carbocyclic group, the substituted C₁-C₆₀ heterocyclic group, the substituted C₃-C₁₀ cycloalkylene group, the substituted C₁-C₁₀ heterocycloalkylene group, the substituted C₃-C₁₀ cycloalkenylene group, the substituted C₁-C₁₀ heterocycloalkenylene group, the substituted C₆-C₆₀ arylene group, the substituted C₁-C₆₀ heteroarylene group, the substituted divalent non-aromatic condensed polycyclic group, the substituted divalent non-aromatic condensed heteropolycyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₃₀ alkenyl group, a C₂-C₃₀ alkynyl group, and a C₁-C₃₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₃₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₃₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

The term “Ph,” as used herein, refers to a phenyl group, the term “Me,” as used herein, refers to a methyl group, the term “Et,” as used herein, refers to an ethyl group, the term “ter-Bu” or “Bu^(t),” as used herein, refers to a tert-butyl group, and the term “OMe,” as used herein, refers to a methoxy group.

The term “biphenyl group,” as used herein, refers to “a phenyl group substituted with a phenyl group.” In some embodiments, the “biphenyl group” may be a substituted phenyl group having a C₆-C₆₀ aryl group as a substituent.

The term “terphenyl group,” as used herein, refers to “a phenyl group substituted with a biphenyl group.” In some embodiments, the “terphenyl group” may be a substituted phenyl group having, as a substituent, a C₆-C₆₀ aryl group substituted with a C₆-C₆₀ aryl group.

* and *′, as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula.

Hereinafter, a light-emitting device according to embodiments will be described in more detail with reference to Examples.

EXAMPLES Example

As a substrate and an anode, a glass substrate with 15 Ωcm² (150 Å) ITO thereon, which was manufactured by Corning Inc., was cut to a size of 50 mm×50 mm×0.7 mm, sonicated by using isopropyl alcohol and pure water for 5 minutes each, and then cleaned by irradiation of ultraviolet rays thereto and exposure to ozone at concurrently for 30 minutes. Then, the resultant glass substrate was loaded onto a vacuum deposition apparatus.

HT3 and F4-TCNQ were co-deposited on the ITO anode at a weight ratio of 9:1 to form a hole injection layer having a thickness of 50 Å. HT3 (400 Å) were deposited on the hole injection layer to form a hole transport layer.

HT18 (100A) was deposited on the hole transport layer to form a hole transport auxiliary layer, and then, H8 and FD5 were co-deposited thereon to a weight ratio of 95:5 to form an emission layer having a thickness of 200 Å, thereby completing formation of a first emission unit.

ET28 (50 Å) was deposited on the first emission unit to form an electron transport (ET)-auxiliary layer.

ET1:Liq (50 Å) were co-deposited on the ET-auxiliary layer to a weight ratio of 9:1 to form an electron transport layer.

A charge generating layer and a hole transport region were formed on the electron transport layer, as described in Examples 1 to 5.

HT18 (50 Å) was deposited on the hole transport region to form a hole transport (HT)-auxiliary layer, and H8 and FD5 (wherein, an amount of FD5 is 1%) were co-deposited thereon to form an emission layer having a thickness of 190 Å, thereby completing formation of a second emission unit.

ET1 and Liq were deposited on the second emission unit to a weight ratio of 95:5 to form an electron transport layer having a thickness of 50 Å, and Yb (15 Å) was deposited thereon to form an electron injection layer, thereby completing formation of an electron transport region.

Ag and Mg (ratio of 5:5) (100 Å) were deposited on the electron transport region to form a cathode, and HT28 (600 Å) was deposited on the cathode to form a capping layer, thereby completing manufacture of an organic light-emitting device.

Example 1

ET36 and Yb (wherein, an amount of Yb is 5 wt %) were co-deposited on the electron transport layer to form an n-type charge generating layer having a thickness of 50 Å, and then HT3 and BiPO₄ (wherein, an amount of BiPO₄ is 5 wt %) were co-deposited thereon to form a p-type charge generating layer having a thickness of 100 Å, thereby completing formation of a charge generating layer.

HT3 (400 Å) was deposited on the charge generating layer to form a hole transport layer, thereby completing formation of a hole transport region.

Example 2

ET36 and Yb (wherein, an amount of Yb is 5 wt %) were co-deposited on the electron transport layer to form an n-type charge generating layer having a thickness of 50 Å, and then BiPO₄ (50 Å) was deposited thereon to form an interlayer, thereby completing formation of a charge generating layer.

HT3 (400 Å) was deposited on the charge generating layer to form a hole transport layer, thereby completing formation of a hole transport region.

Example 3

ET36 and Yb (wherein, an amount of Yb is 5 wt %) were co-deposited on the electron transport layer to form an n-type charge generating layer having a thickness of 50 Å, and then BiPO₄ (50 Å) was deposited thereon to form an interlayer. HT3 and F4-TCNQ (wherein, an amount of F4-TCNQ is 2 wt %) were co-deposited on the interlayer to form a p-type charge generating layer having a thickness of 150 Å, thereby completing formation of a charge generating layer.

HT3 (400 Å) was deposited on the charge generating layer to form a hole transport layer, thereby completing formation of a hole transport region.

Example 4

ET36 and Yb (wherein, an amount of Yb is 5 wt %) were co-deposited on the electron transport layer to form an n-type charge generating layer having a thickness of 50 Å, and then HT3 and BiPO₄ (wherein, an amount of BiPO₄ is 5 wt %) were co-deposited thereon to form a p-type charge generating layer having a thickness of 100 Å, thereby completing formation of a charge generating layer.

HT3 and F4-TCNQ (wherein, an amount of F4-TCNQ is 2 wt %) were deposited on the charge generating layer to form a first hole transport layer having a thickness of 100 Å, and HT3 (100 Å) was deposited thereon to form a second hole transport layer, thereby completing formation of a hole transport region.

Example 5

ET36 and Yb (wherein, an amount of Yb is 5%) were co-deposited on the electron transport layer to form an n-type charge generating layer having a thickness of 50 Å, and then BiPO₄ (50 Å) was deposited thereon to form an interlayer. HT3 and F4-TCNQ (wherein, an amount of F4-TCNQ is 2 wt %) were co-deposited on the interlayer to form a p-type charge generating layer having a thickness of 150 Å, thereby completing formation of a charge generating layer.

HT3 and F4-TCNQ (wherein, an amount of F4-TCNQ is 2 wt %) were deposited on the charge generating layer to form a first hole transport layer having a thickness of 100 Å, and HT3 (100 Å) was deposited thereon to form a second hole transport layer, thereby completing formation of a hole transport region.

Comparative Example 1

An organic light-emitting device was manufactured in substantially the same manner as in Example 1, except that ET36 and Yb (wherein, an amount of Yb is 1 wt %) were co-deposited to form an n-type charge generating layer having a thickness of 150 Å, and HT3 and F4-TCNQ (wherein, an amount of F4-TCNQ is 2 wt %) were co-deposited to form a p-type charge generating layer, thereby completing formation of a charge generating layer, and HT3 (430 Å) was deposited on the charge generating layer to form a hole transport layer.

Evaluation Example: Evaluation of Driving Characteristics of Device

With respect to each of the organic light-emitting devices manufactured according to Examples 1 to 5 and Comparative Example 1, driving voltage (V), current density (mA/cm²) at the same voltage (5.0 V), efficiency (Cd/A), and white-color luminescence efficiency (lm/W) were measured, and results thereof are shown in Table

TABLE 1 Current White-color Driving density luminescence voltage (mA/cm²) Efficiency efficiency (V) (@ 5.0 V) (Cd/A) (lm/W) Example 1 4.6 11.9 10.0 2.4 Example 2 4.2 12.4 9.7 2.1 Example 3 6.8 10.5 14.1 5.0 Example 4 7.4 9.2 16.0 6.8 Example 5 7.5 9.1 16.1 6.7 Comparative 7.8 10.3 14.2 5.7 Example 1

Referring to Table 1, the organic light-emitting devices manufactured according to Examples 1 to 3 may have reduced driving voltage and high current density at the same voltage, as compared to the organic light-emitting device manufactured according to Comparative Example 1, and may have emission efficiency that is equal to or not significantly lower than the organic light-emitting device manufactured according to Comparative Example 1. In addition, it be seen from Table 1 that the organic light-emitting devices manufactured according to Examples 4 and 5 may have reduced driving voltage and high efficiency, as compared to the organic light-emitting device manufactured according to Comparative Example 1.

A charge generating layer of the organic light-emitting device may efficiently generate charges, and accordingly, a high-quality organic light-emitting device may be embodied.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims, and equivalents thereof. 

What is claimed is:
 1. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; m emission units stacked between the first electrode and the second electrode, each emission unit comprising at least one emission layer; and m−1 charge generating layers respectively located between two adjacent emission units among the m emission units, each of the charge generating layers comprising one n-type charge generating region and one p-type charge generating region, wherein m is an integer of 2 or more, and at least one of the m−1 p-type charge generating regions comprises a phosphate-containing compound.
 2. The organic light-emitting device of claim 1, wherein the phosphate-containing compound comprises a compound containing at least one selected from phosphoric acid (H₃PO₄), a dihydrogen phosphate ion (H₂PO₄ ⁻), a hydrogen phosphate ion (HPO₄ ²⁻), a phosphate ion (PO₄ ³⁻), and a pyrophosphate ion (P₂O₇ ⁴⁻).
 3. The organic light-emitting device of claim 1, wherein the phosphate-containing compound comprises at least one selected from phosphoric acid (H₃PO₄), an alkali metal phosphate, an alkaline earth metal phosphate, a transition metal phosphate, a post-transition metal phosphate, a lanthanide metal phosphate, an actinide metal phosphate, a metalloid phosphate, ammonium phosphate, a transition metal ammonium phosphate, and hydrates of any one of the aforementioned.
 4. The organic light-emitting device of claim 1, wherein the phosphate-containing compound comprises at least one selected from H₃PO₄, Ag₃PO₄, Ba(PO₃)₂, AlPO₄, BPO₄, Ba₂P₂O₇, Ba₃(PO₄)₂, BiPO₄, CaHPO₄, Ca₃(PO₄)₂, Ca₄(PO₄)₂O, Cd₃(PO₄)₂, CePO₄, Co₃(PO₄)₂, CrPO₄, CsH₂PO₄, Cs₂HPO₄, Cs₂PO₄, Cs₃PO₄, Cu₃(PO₄)₂, ErPO₄, FeO₈H₄P₂, FePO₄, Fe₄(P₂O₇)₃, GaPO₄, Hg₃(PO₄)₂, InPO₄, K₂HPO₄, KH₂PO₄, LaPO₄, LaPO₄.5H₂O, LiH₂PO₄, Li₂HPO₄, Li₃PO₄, Mn₃(PO₄)₂, MgHPO₄, MgNH₄PO₄.6H₂O, Mg₂P₂O₇, (NH₄)₃PO₄, NaH₂PO₄, Na₂PO₄, NdPO₄, Ni₃(PO₄)₂, Pb₃(PO₄)₃, PrPO₄, RbH₂PO₄, Rb₂HPO₄, Rb₃PO₄, SbPO₄, ScPO₄, Sr₃(PO₄)₂, Th₃(PO₄)₄, Tl₃PO₄, TmPO₄, U(PO₄)₂, YPO₄, Zn₂P₂O₇, Zn₃(PO₄)₂, Zr₃(PO₄)₄, and Bi₃PO₄.
 5. The organic light-emitting device of claim 1, wherein the at least one of the m−1 p-type charge generating regions comprises at least one of a p-type charge generating layer and an interlayer.
 6. The organic light-emitting device of claim 5, wherein the at least one of the m−1 p-type charge generating regions comprises a p-type charge generating layer, and the p-type charge generating layer comprises the phosphate-containing compound.
 7. The organic light-emitting device of claim 5, wherein the at least one of the m−1 p-type charge generating regions comprises a p-type charge generating layer, and the p-type charge generating layer comprises the phosphate-containing compound and a hole transport material.
 8. The organic light-emitting device of claim 7, wherein the p-type charge generating layer comprises the phosphate-containing compound in an amount in a range of 0.01 parts by weight to 49.99 parts by weight based on 100 parts by weight of the hole transport material.
 9. The organic light-emitting device of claim 7, wherein the hole transport material is selected from compounds represented by Formulae 201, 202, and 301-2:

wherein, in Formulae 201, 202, and 301-2, A₃₀₁ to A₃₀₄ are each independently selected from a benzene ring, a naphthalene ring, a phenanthrene ring, a fluoranthene ring, a triphenylene ring, a pyrene ring, a chrysene ring, a pyridine ring, a pyrimidine ring, an indene ring, a fluorene ring, a spiro-bifluorene ring, a benzofluorene ring, a dibenzofluorene ring, an indole ring, a carbazole ring, a benzocarbazole ring, a dibenzocarbazole ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a naphthofuran ring, a benzonaphthofuran ring, a dinaphthofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a naphthothiophene ring, a benzonaphthothiophene ring, and a dinaphthothiophene ring, X₃₀₁ is O, S, Or N-[(L₃₀₄)_(xb4)-R₃₀₄], L₂₀₁ to L₂₀₄ and L₃₀₁ to L₃₀₃ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, L₂₀₅ is selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted or unsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstituted C₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, xa1 to xa4 are each independently an integer from 0 to 3, xa5 is an integer from 1 to 10, xb1 to xb4 are each independently an integer from 0 to 5, xb22 and xb23 are each independently 0, 1, or 2, R₂₀₁ to R₂₀₄ and Q₂₀₁ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, R₃₀₁ to R₃₀₄ are each independently selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(G₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂), R₃₁₁ to R₃₁₄ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and Q₃₁ to Q₃₃ and Q₃₀₁ to Q₃₀₃ are each independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.
 10. The organic light-emitting device of claim 5, wherein the at least one of the m−1 p-type charge generating regions comprises an interlayer, and the interlayer comprises the phosphate-containing compound.
 11. The organic light-emitting device of claim 5, wherein the at least one of the m−1 p-type charge generating regions comprises an interlayer, and the interlayer consists of the phosphate-containing compound.
 12. The organic light-emitting device of claim 5, wherein the at least one of the m−1 p-type charge generating regions comprises a p-type charge generating layer and an interlayer, the interlayer is located between the n-type charge generating region and the p-type charge generating layer, the p-type charge generating layer comprises a phosphate-free compound and does not include the phosphate-containing compound, and the interlayer comprises the phosphate-containing compound.
 13. The organic light-emitting device of claim 10, wherein a thickness of the interlayer is 1 Å to 3,000 Å.
 14. The organic light-emitting device of claim 1, wherein the m−1 n-type charge generating regions comprise a metal-free compound comprising at least one selected from a π-electron-deficient nitrogen-containing ring, a metal-containing material, and any combination thereof.
 15. The organic light-emitting device of claim 1, wherein the m−1 n-type charge generating regions comprise a compound represented by Formula 601 below, a metal, a metal complex, or any combination thereof: [Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  Formula 601 wherein, in Formula 601, Ar₆₀₁ is a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group, xe11 is 1, 2, or 3, L₆₀₁ is selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, xe1 is an integer from 0 to 5, R₆₀₁ is selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂), Q₆₀₁ to Q₆₀₃ are each independently a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and xe21 is an integer from 1 to
 5. 16. The organic light-emitting device of claim 1, wherein m is 2, the m emission units comprise a first emission unit and a second emission unit that are sequentially stacked from the first electrode, the m−1 charge generating layers comprise a first charge generating layer, the first charge generating layer is located between the first emission unit and the second emission unit, the first charge generating layer comprises a first n-type charge generating region and a first p-type charge generating region, the first n-type charge generating region is located between the first electrode and the first p-type charge generating region, and the first p-type charge generating region comprises the phosphate-containing compound.
 17. The organic light-emitting device of claim 1, wherein m is 3, the m emission units comprise a first emission unit, a second emission unit, and a third emission unit that are sequentially stacked from the first electrode, the m−1 charge generating layers comprise a first charge generating layer and a second charge generating layer, the first charge generating layer is located between the first emission unit and the second emission unit, the second charge generating layer is located between the second emission unit and the third emission unit, the first charge generating layer comprises a first n-type charge generating region and a first p-type charge generating region, the second charge generating layer comprises a second n-type charge generating region and a second p-type charge generating region, the first n-type charge generating region is located between the first electrode and the first p-type charge generating region, the second n-type charge generating region is located between the first electrode and the second p-type charge generating region, and at least one selected from the first p-type charge generating region and the second p-type charge generating region comprises the phosphate-containing compound.
 18. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; m emission units stacked between the first electrode and the second electrode, each emission unit comprising at least one emission layer; and m−1 charge generating layers respectively located between two adjacent emission units among the m emission units, each of the charge generating layers comprising one n-type charge generating region and one p-type charge generating region, wherein m is an integer of 2 or more, at least one of the m emission units further comprises a hole transport region between the first electrode and the emission layer, and at least one of the p-type charge generating region and the hole transport region comprises a phosphate-containing compound.
 19. The organic light-emitting device of claim 18, wherein the hole transport region comprises a first hole transport layer and a second hole transport layer, the first hole transport layer is located between the first electrode and the second hole transport layer, the first hole transport layer comprises a p-dopant, and at least one selected from the p-type charge generating region and the first hole transport layer comprises a phosphate-containing compound.
 20. The organic light-emitting device of claim 18, wherein the p-type charge generating region comprises at least one selected from a p-type charge generating layer and an interlayer, the hole transport region comprises a first hole transport layer and a second hole transport layer, the first hole transport layer is located between the first electrode and the second hole transport layer, the first hole transport layer comprises a p-dopant, and at least one selected from the p-type charge generating layer, the interlayer, and the first hole transport layer comprises a phosphate-containing compound. 